net: fix infoleak in rtnetlink

commit 5f8e44741f9f216e33736ea4ec65ca9ac03036e6 upstream.

The stack object “map” has a total size of 32 bytes. Its last 4
bytes are padding generated by compiler. These padding bytes are
not initialized and sent out via “nla_put”.

Signed-off-by: Kangjie Lu <kjlu@gatech.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2: adjust context, indentation]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index e77373a..72a7ed8 100644 (file)
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -920,14 +920,16 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
                NLA_PUT_STRING(skb, IFLA_IFALIAS, dev->ifalias);
 
        if (1) {
-               struct rtnl_link_ifmap map = {
-                       .mem_start   = dev->mem_start,
-                       .mem_end     = dev->mem_end,
-                       .base_addr   = dev->base_addr,
-                       .irq         = dev->irq,
-                       .dma         = dev->dma,
-                       .port        = dev->if_port,
-               };
+               struct rtnl_link_ifmap map;
+
+               memset(&map, 0, sizeof(map));
+               map.mem_start   = dev->mem_start;
+               map.mem_end     = dev->mem_end;
+               map.base_addr   = dev->base_addr;
+               map.irq         = dev->irq;
+               map.dma         = dev->dma;
+               map.port        = dev->if_port;
+
                NLA_PUT(skb, IFLA_MAP, sizeof(map), &map);
        }